@PURPOSE@ Obtain the system root directory
@DESC@
Obtrains the system root directory in 'config' if available.
+@SINCE@ 2.10.92
@@
@RET@ void
to the cache directories in order to allow people to generate caches at
the build time. Note that this causes changing current config. i.e.
this function calls FcConfigSetCurrent() internally.
+@SINCE@ 2.10.92
@@